As above what is ACE and how to tell if car has it, 2006 HSE, the rear ARB bushes are shot so just getting some knowledge before deciding on what to do

Active cornering enhancement, chech to see if you have a valve block mounted on the o/s chassis rain, inline with the B post. 2008 G4 RRSport TDV8 current
2009 TDCi 90 current
2018 Discovery 5 HSE lux current
1994 Dakar current

If you have front Brembo calipers, you have ACE (unless they have been retro-fitted)

Valve block on the O/S of the chassis

Extra fluid reservoir next to the air filter

cheers chaps , is the block visible in the engine bay or in wheel arch or under car ?

Easiest way to tell is the reservoir. Its on the front offside, it has a picture of the car with left and right curved arrows.

Ah just looked and no reservoir